Get the filehandler/rollbackhandler to build.
Port file client to use the new API.

This commit ports fileclient into the new API.
Port the applications to the new fileproxy code.

This commit ports fileserver, keynegoserver, and rollbackserver to use more
idiomatic Go style and to use the changed versions of ResourceMaster and
RollbackMaster.

These versions haven't been tested yet.
Fix the code to get all fileclient tests to pass.

This version of the code can run in the context of the install.sh script and can
successfully run all fileclient tests.
Remove unnecessary functions.

This commit removes the functions that expose the internal structure of the
Signer and Verifier in keys.go
Port fileclient to use standard key methods.
Port fileserver to use standard tao/key.go funcs.
Port the rollback server to use keys functions.
Remove superfluous key code.

This commit removes the key code that duplicates the code in keys.go, and it
refactors the keynegoserver code into tao/net.
Clean up the fileproxy files.

This commit renames the files and gets rid of the scripts, since fileproxy now
works in the standard install.sh framework.
Make fileclient create a test file.

This commit creates a simple test file in fileclient rather than relying on the
user to do it. It also adds a run.sh script that contains the actions needed to
get fileproxy to run in the context of a directory created by install.sh -notpm.